The present invention generally relates to apparati, methods, and chemistries employed in the home for laundering clothing and fabrics. More particularly, it relates to a new and improved method, apparatus, and chemistry for home laundering of a fabric load using a wash liquor comprising a multi-phase mixture of a substantially inert working fluid (IWF) and at least one washing adjuvant.
As used herein, the terms “substantially non-reactive” or “substantially inert” when used to describe a component of a wash liquor or washing fluid, means a non-solvent, non-detersive fluid that under ordinary or normal washing conditions, e.g. at pressures of 0 Pa to 0.5×106 Pa and temperatures of from about 1° C. to about 100° C., does not appreciably react with the fibers of the fabric load being cleaned, the stains and soils on the fabric load, or the washing adjuvants combined with the component to form the wash liquor. An IWF ideally does very little or nothing except act as a carrier or vehicle to carry an adjuvant to the clothes so that the adjuvant can work on the clothes.
Home laundering of fabrics is usually performed in an automatic washing machine and occasionally by hand. These methods employ water as the major component of the washing fluid. Cleaning adjuvants such as detergents, enzymes, bleaches and fabric softeners are added and mixed with the water at appropriate stages of the wash cycle to provide cleaning, whitening, softening, and the like.
Although improvements in automatic washing machines and in cleaning agent formulations are steadily being made, as a general rule, conventional home laundering methods consume considerable amounts of water, energy, and time. Water-based methods are not suitable for some natural fiber fabrics, such as silks, woolens and linens, so that whole classes of garments and fabrics cannot be home laundered, but instead, must be sent out for professional dry cleaning. During water washing, the clothes become saturated with water and some fibers swell and absorb water. After washing, the water must be removed from the clothes. Typically, this is performed in a two-step process including a hard spin cycle in the washer and a full drying cycle in an automatic dryer. The hard spin cycles tend to cause undesirable wrinkling. Even after spinning, drying cycle times are undesirably long.
The solution to this problem was the advent of the traditional dry cleaning business. Consumers had to travel to the dry cleaners, drop off clothes, pay for dry cleaning, and pick the clothes up. While the dry cleaning process is useful to the consumer, it plays terrible havoc with the environment. Traditional dry cleaning uses halogenated hydrocarbons, such as perchloroethylene (nefariously known as “perc”). Because the use of perc is calamitous, strict environmental regulations exist to control its use and disposition. The stricter controls sent many in the dry cleaning industry towards petroleum-based solvents. These solvents are inflammable and are smog-producers. Accordingly, the use of these solvents in the home is out of the question.
A further non-aqueous solvent based washing method employs liquid or supercritical carbon dioxide solvent as a washing liquid. As described in U.S. Pat. No. 5,467,492, highly pressurized vessels are required to perform this washing method. In accordance with these methods, pressures of about 3.45×106 Pa to 6.89×106 Pa are required. Pressures of up to about 0.206×106 Pa are approved for use in the home. The high pressure conditions employed in the carbon dioxide create safety hazards that make them unsuitable for residential use.
Various perfluorocarbon materials have been employed alone or in combination with cleaning additives for washing printed circuit boards and other electrical substrates, as described for example in U.S. Pat. No. 5,503,681. Spray cleaning of rigid substrates is very different from laundering soft fabric loads. Moreover, cleaning of electrical substrates is performed in high technology manufacturing facilities employing a multi-stage apparatus which is not readily adapted for home use.